A method for preparing Ti6Al4V alloy powder

Abstract

This invention provides a method for preparing Ti6Al4V alloy powder, wherein the preparation method involves reducing titanium dioxide to produce a first reduced powder, TiO2. x Vanadium oxide and calcium oxide were reduced with an aluminum reducing agent to obtain 6Al4V alloy powder, and then the first reduced powder TiO2 was... x After being mixed and sintered with 6Al4V alloy powder, Ti6Al4V alloy powder is deoxidized to obtain Ti6Al4V alloy powder with low oxygen content and high purity. The preparation method does not require the preparation of sponge titanium, avoids the smelting process, has low cost, and has broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of titanium alloy preparation technology, and in particular to a method for preparing Ti6Al4V alloy powder. Background Technology

[0002] Titanium alloys possess excellent properties and are important functional and structural materials. However, the traditional forging process for titanium alloys is lengthy, and due to titanium's high chemical reactivity, low thermal conductivity, and high hardness and strength, titanium alloy materials are difficult to cut. This results in a high buy-scrap ratio and low material utilization in parts manufactured from rolled products, leading to high production costs. Therefore, near-net-shape processing of titanium alloy parts is an important development direction, including powder pressing and sintering, hot isostatic pressing, powder injection molding, and powder additive manufacturing. These methods offer shorter processes and higher material utilization, but require high-quality metal powders as raw materials.

[0003] Ti-6Al-4V alloy is the flagship titanium alloy, accounting for over 70% of all titanium alloys. The basic raw material requirement for near-net-shape forming of Ti-6Al-4V alloy parts is high-quality Ti-6Al-4V alloy powder. Currently, the mainstream preparation methods for Ti-6Al-4V alloy powder are the hydrogenation-dehydrogenation method and the atomization method. The hydrogenation-dehydrogenation method involves first absorbing hydrogen and crushing titanium alloy ingots / shavings to the required size, then vacuum dehydrogenating them. The powder morphology is irregular, the purity depends on the purity of the raw materials, and controlling the increase in oxygen content during the preparation process is relatively difficult. The atomization method includes three steps: melting, atomization, and cooling. The melting method can be vacuum induction melting, plasma arc melting, or induction drip melting. After melting, the liquid metal is atomized into metal droplets by high-pressure gas, or metal droplets are produced by centrifugal force generated by high-speed rotation, and then rapidly cooled in a protective atmosphere to become spherical metal particles. However, the atomization method requires the use of expensive titanium alloy rods / wires, etc., and consumes a lot of electricity and gas. The price of atomized powder is generally as high as several hundred to several thousand yuan per kilogram.

[0004] CN111318684A discloses Ti6Al4V alloy powder, its preparation method, and 3D printed products. The preparation method includes the following steps: placing hydrogenated dehydrogenated titanium powder in a ball mill, adding ethanol, and ball milling to obtain spherical titanium powder; then mixing the spherical titanium powder with aluminum powder and vanadium powder uniformly to obtain Ti6Al4V alloy powder. This method uses ball milling not to make the particles finer, but to adjust the particle morphology; the subsequent mixing of the spherical titanium powder with aluminum and vanadium powder is a simple physical mixing process without alloying, resulting only in a mixture containing the nominal components of Ti6Al4V alloy. The preparation of this mixture relies on high-quality titanium and vanadium powders, resulting in high raw material costs.

[0005] CN112809013A and others disclose a method for preparing Ti-6Al-4V alloy powder. The method uses a full-component mixing and sintering-deep deoxidation technology to prepare Ti-6Al-4V alloy powder, which can expand the sources of vanadium powder and titanium powder, but the raw materials still mainly rely on vanadium powder and titanium powder.

[0006] Therefore, it is necessary to develop a method for preparing Ti-6Al-4V alloy powder that does not rely on vanadium powder and titanium powder, so as to reduce the cost of raw materials. Summary of the Invention

[0007] In view of the problems existing in the prior art, the present invention provides a method for preparing Ti6Al4V alloy powder. The preparation method can directly prepare Ti6Al4V alloy powder from titanium dioxide and vanadium oxide as raw materials, without the need for titanium powder and vanadium powder as raw materials, without the need for the preparation of sponge titanium and without the need for a smelting process. The overall process is short and the preparation cost is low.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] This invention provides a method for preparing Ti6Al4V alloy powder, the method comprising the following steps:

[0010] (1) Titanium dioxide is reduced by a first reducing agent, and the resulting first reduced raw material is processed by a first wet process to obtain first reduced powder TiO2. x Where x≤0.5; the mixture of vanadium oxide and calcium oxide undergoes a second reduction with a second reducing agent and a second auxiliary agent, and the resulting second reducing material is subjected to a second wet process to obtain 6Al4V alloy powder, wherein the mass ratio of vanadium to aluminum in the 6Al4V alloy powder is 3.5~4.5:5.5~6.75; the second reducing agent includes aluminum;

[0011] (2) Mix the 6Al4V alloy powder and the first reducing powder TiO2. x After sintering, the oxygen-containing Ti6Al4V alloy powder is subjected to deoxidation treatment and a third wet process to obtain Ti6Al4V alloy powder.

[0012] The method for preparing Ti6Al4V alloy powder provided by this invention can directly prepare Ti6Al4V alloy powder from titanium dioxide and vanadium oxide. The process is simple, the cost is low, and the raw materials are widely available, which greatly reduces the production cost of Ti6Al4V alloy powder.

[0013] This invention transforms the alumina-enriched byproduct phase, which is originally impossible to separate by wet processing after reduction, into a phase that can be separated by wet processing by adding calcium oxide and a reduction aid to the reduction of vanadium oxide. This eliminates the need for slag-metal separation and other operations to obtain vanadium-aluminum alloys. Furthermore, a second wet process can be used to separate the aluminum-calcium-oxygen phase from the 6Al4V alloy to obtain 6Al4V alloy powder. This 6Al4V alloy powder can then be combined with the first reducing powder, TiO2. x The preparation of Ti6Al4V alloy powder by mixing requires only three reduction steps to obtain Ti6Al4V alloy powder with low oxygen content, which significantly reduces costs.

[0014] Preferably, when the first reducing agent in step (1) is aluminum, the molar ratio of the first reducing agent to titanium dioxide is 1 to 1.33:1, for example, it can be 1:1, 1.04:1, 1.08:1, 1.11:1, 1.15:1, 1.19:1, 1.22:1, 1.26:1, 1.3:1 or 1.33:1, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0015] Preferably, when the first reducing agent is aluminum, the first reducing agent includes any one or a combination of at least two of the following: powder, chips, or granules, wherein typical but non-limiting combinations are a combination of powder and chips, a combination of powder and granules, or a combination of granules and chips.

[0016] Preferably, when the first reducing agent is aluminum, calcium oxide is added during the first reduction.

[0017] Preferably, when the first reducing agent is aluminum, the molar ratio of calcium oxide to the first reducing agent is 0.6 to 2:1, for example, it can be 0.6:1, 0.8:1, 1:1, 1.1:1, 1.3:1, 1.4:1, 1.6:1, 1.7:1, 1.9:1 or 2:1, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0018] When aluminum is used as the first reducing agent in this invention, the cost is lower than that of magnesium as the reducing agent. Calcium oxide is added to optimize the phase state of the aluminum reduction byproducts, allowing them to be separated from the first reduced powder via wet processing, eliminating the need for slag-metal separation to obtain the first reduced powder. Furthermore, this invention further optimizes the molar ratio of calcium oxide to the first reducing agent within the aforementioned range, effectively ensuring the reduction effect and preventing the formation of the sparingly soluble aluminum phase.

[0019] Preferably, when the first reducing agent is aluminum, a first auxiliary agent is added during the first reduction.

[0020] Preferably, when the first reducing agent is aluminum, the first auxiliary agent includes any one or a combination of at least two of the following: anhydrous CaCl2, KCl, NaCl, CaCl2-KCl eutectic salt, CaCl2-NaCl eutectic salt, CaCl2-LiCl eutectic salt, KCl-NaCl eutectic salt, AlCl3-CaCl2 eutectic salt, AlCl3-KCl eutectic salt, or AlCl3-NaCl eutectic salt. Typical but non-limiting combinations include anhydrous CaCl2 and KCl, CaCl2-KCl eutectic salt and KCl, anhydrous CaCl2 and CaCl2-NaCl eutectic salt, anhydrous CaCl2 and KCl-NaCl eutectic salt, and AlCl3-KCl eutectic salt and KCl.

[0021] The present invention further preferably uses a calcium-containing first auxiliary agent when the first reducing agent is aluminum, so as to better ensure the formation of the wet-separable aluminum phase during the first reduction process.

[0022] Preferably, when the first reducing agent is aluminum, the weight ratio of the first auxiliary agent to titanium dioxide is 0.05 to 3:1, for example, it can be 0.05:1, 0.38:1, 0.71:1, 1.04:1, 1.37:1, 1.69:1, 2.02:1, 2.35:1, 2.68:1 or 3:1, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0023] Preferably, when the first reducing agent in step (1) is aluminum, the temperature of the first reduction is 700 to 1400°C, for example, it can be 700°C, 800°C, 860°C, 930°C, 1000°C, 1060°C, 1130°C, 1200°C, 1260°C, 1330°C or 1400°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0024] Preferably, when the first reducing agent is aluminum, the first reduction time is 0.25 to 24 hours, for example, it can be 0.25 hours, 0.5 hours, 1 hour, 2 hours, 3 hours, 5 hours, 10 hours, 12 hours, 13 hours or 24 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0025] Preferably, when the first reducing agent is aluminum, the atmosphere for the first reduction is a vacuum or a protective atmosphere.

[0026] Preferably, when the first reducing agent is aluminum, the protective atmosphere for the first reduction includes any one or a combination of at least two of argon, hydrogen, or helium, wherein typical but non-limiting combinations are combinations of argon and hydrogen, helium and hydrogen, and argon and helium.

[0027] Preferably, when the first reducing agent in step (1) is magnesium, the molar ratio of the first reducing agent to titanium dioxide is 2 to 4:1, for example, it can be 2:1, 2.3:1, 2.5:1, 2.7:1, 2.9:1, 3.2:1, 3.4:1, 3.6:1, 3.8:1 or 4:1, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0028] Preferably, when the first reducing agent is magnesium, the first reducing agent includes any one or a combination of at least two of the following: powder, shavings, or granules, wherein typical but non-limiting combinations are a combination of powder and shavings, a combination of granules and shavings, or a combination of powder and granules.

[0029] Preferably, when the first reducing agent is magnesium, the first auxiliary agent includes any one or a combination of at least two of anhydrous MgCl2, MgCl2-KCl eutectic salt, MgCl2-NaCl eutectic salt, or MgCl2-CaCl2 eutectic salt. Typical but non-limiting combinations are combinations of anhydrous MgCl2 and MgCl2-KCl eutectic salt, combinations of MgCl2-CaCl2 eutectic salt and MgCl2-KCl eutectic salt, and combinations of anhydrous MgCl2 and MgCl2-CaCl2 eutectic salt.

[0030] Preferably, when the first reducing agent is magnesium, the weight ratio of the first auxiliary agent to titanium dioxide is 0.05 to 3:1, for example, it can be 0.05:1, 0.30:1, 0.70:1, 1.00:1, 1.30:1, 1.65:1, 2.05:1, 2.35:1, 2.65:1 or 3:1, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0031] Preferably, when the first reducing agent in step (1) is magnesium, the temperature of the first reduction is 600 to 900°C, for example, it can be 600°C, 630°C, 660°C, 700°C, 730°C, 760°C, 800°C, 830°C, 860°C or 900°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0032] Preferably, when the first reducing agent is magnesium, the first reduction time is 0.25 to 24 hours, for example, it can be 0.25 hours, 0.5 hours, 1 hour, 2 hours, 3 hours, 5 hours, 10 hours, 12 hours, 13 hours or 24 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0033] Preferably, when the first reducing agent is magnesium, the atmosphere for the first reduction includes any one or a combination of at least two of argon, hydrogen, or helium, wherein typical but non-limiting combinations are combinations of argon and hydrogen, combinations of argon and helium, and combinations of helium and hydrogen.

[0034] Preferably, in step (1), the molar ratio of the second reducing agent to vanadium oxide is [(2y+2)a+(2y+3.333)b]:(a+b), where a / (a+b) is the molar percentage of vanadium trioxide in the vanadium oxide, b / (a+b) is the molar percentage of vanadium pentoxide in the vanadium oxide, and y is the molar ratio of aluminum to vanadium in the 6Al4V alloy powder.

[0035] Since the nominal composition requirement for Ti6Al4V is an Al mass content of 5.5%-6.75% and a V mass content of 3.5%-4.5%, the upper limit of the aluminum to vanadium molar ratio in 6Al4V alloy powder is 6.75 / 27 / 3.5*51 = 3.642, and the lower limit of the aluminum to vanadium molar ratio is 5.5 / 27 / 4.5*51 = 2.309. That is, the range of y values ​​is 2.309 to 3.642, for example, it can be 2.039, 2.04, 2.1, 2.3, 2.4, 2.5, 2.8, 2.833, 3.0, 3.1, 3.2, 3.5, 3.6 or 3.642, etc.

[0036] Further optimization of the 6Al4V alloy powder yields an aluminum to vanadium mass ratio of 1.5, i.e., a y value of 2.833. In this case, the molar ratio of the second reducing agent to vanadium oxide is preferably (7.666a+8.999b):(a+b).

[0037] This invention involves only one reduction step for the preparation of 6Al4V alloy powder, as shown by the chemical equation:

[0038] aV2O3+bV2O5+((2y+2)a+(2y+3.333)b)Al=(2a+2b)VAl y The amount of reducing agent required for the 6Al4V product can be directly calculated using the formula (a+5 / 3b)Al2O3. The corresponding product can be obtained by directly controlling the amount of reducing agent added.

[0039] The present invention further optimizes the molar ratio of the second reducing agent to vanadium oxide to the above-mentioned values, thereby ensuring that the mass ratio of aluminum and vanadium in the 6Al4V alloy powder is within the nominal range allowed by the 6Al4V alloy. The present invention uses the above chemical equation to calculate the molar ratio of the second reducing agent to vanadium oxide only for ease of calculation; however, the actual substance produced is not the Al2O3 phase, but rather an aluminum-calcium-oxygen phase that is easily dissolved in dilute acid.

[0040] Preferably, the second reducing agent comprises any one or a combination of at least two of the following: powder, crumbs, or granules, wherein typical but non-limiting combinations are a combination of powder and crumbs, a combination of granules and crumbs, or a combination of powder and granules.

[0041] Preferably, the molar ratio of calcium oxide to the second reducing agent in the second reduction is 0.6 to 2:1, for example, it can be 0.6:1, 0.8:1, 1:1, 1.1:1, 1.3:1, 1.4:1, 1.6:1, 1.7:1, 1.9:1 or 2:1, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0042] The present invention further preferably controls the molar ratio of calcium oxide to reducing agent within the above range, which is more conducive to the formation of reduction by-products that can be wet-processed, and avoids the 6Al4V alloy powder carrying high oxygen content or impurities.

[0043] Preferably, the second auxiliary agent comprises any one or a combination of at least two of anhydrous CaCl2, CaCl2-KCl eutectic salt, CaCl2-NaCl eutectic salt, or CaCl2-LiCl eutectic salt, wherein typical but non-limiting combinations are combinations of anhydrous CaCl2 and CaCl2-KCl eutectic salt, combinations of CaCl2-NaCl eutectic salt and CaCl2-KCl eutectic salt, and combinations of anhydrous CaCl2 and CaCl2-LiCl eutectic salt.

[0044] Preferably, the weight ratio of the second auxiliary agent to vanadium oxide is 0.05 to 3:1, for example, it can be 0.05:1, 0.35:1, 0.70:1, 1.05:1, 1.35:1, 1.65:1, 2.0:1, 2.35:1, 2.65:1 or 3:1, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0045] Preferably, the second reduction temperature is 700 to 1400°C, for example, it can be 700°C, 770°C, 850°C, 930°C, 1000°C, 1080°C, 1160°C, 1240°C, 1320°C or 1400°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0046] Preferably, the second reduction time is 0.25 to 24 hours, for example, it can be 0.25 hours, 0.5 hours, 1 hour, 2 hours, 3 hours, 5 hours, 10 hours, 12 hours, 13 hours or 24 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0047] Preferably, the second reducing atmosphere is a vacuum or a protective atmosphere.

[0048] Preferably, the protective atmosphere for the second reduction includes any one or a combination of at least two of argon, hydrogen, or helium, wherein typical but non-limiting combinations are combinations of argon and hydrogen, helium and hydrogen, or argon and helium.

[0049] Preferably, the mixing process in step (2) includes: mixing the first reducing powder TiO2... x It is mixed with 6V4Al alloy powder, crushed, and granulated.

[0050] Preferably, the crushing method includes any one or a combination of at least two of ball milling, roller milling, stirred milling, or air jet milling, wherein typical but non-limiting combinations are a combination of ball milling and roller milling, a combination of stirred milling and roller milling, a combination of ball milling and stirred milling, and a combination of air jet milling and roller milling.

[0051] Preferably, the granulation method includes any one of spray granulation, roller granulation, or pressure granulation.

[0052] Preferably, the sintering temperature is 900–1400°C, for example, 900°C, 950°C, 1010°C, 1060°C, 1120°C, 1170°C, 1230°C, 1280°C, 1340°C, or 1400°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0053] Preferably, the sintering time is 0.25 to 24 hours, for example, it can be 0.25 hours, 0.5 hours, 1 hour, 2 hours, 3 hours, 5 hours, 10 hours, 12 hours, 13 hours or 24 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0054] Preferably, the sintering atmosphere is a vacuum or a protective atmosphere.

[0055] Preferably, the protective atmosphere for sintering includes any one or a combination of at least two of hydrogen, argon, or helium, wherein typical but non-limiting combinations are a combination of hydrogen and argon, a combination of helium and argon, or a combination of hydrogen and helium.

[0056] Preferably, when the deoxidizer in step (2) contains magnesium, the mass ratio of the oxygen-containing Ti6Al4V alloy powder to the deoxidizer is 1:0.05 to 0.6, for example, it can be 1:0.05, 1:0.1, 1:0.15, 1:0.2, 1:0.25, 1:0.3, 1:0.35, 1:0.4, 1:0.45, 1:0.5, 1:0.55 or 1:0.6, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0057] Preferably, when the deoxidizing agent in the deoxidation treatment contains magnesium, the deoxidizing agent comprises any one or a combination of at least two of the following: powder, shavings, or granules, wherein typical but non-limiting combinations are a combination of powder and shavings, a combination of powder and granules, or a combination of granules and shavings.

[0058] Preferably, when the deoxidizing agent in the deoxidation treatment contains magnesium, a third auxiliary agent is added during the deoxidation treatment.

[0059] Preferably, when the deoxidizer in the deoxidation treatment contains magnesium, the third auxiliary agent includes any one or a combination of at least two of anhydrous MgCl2, MgCl2-CaCl2 eutectic salt, MgCl2-NaCl eutectic salt, or MgCl2-KCl eutectic salt. Typical but non-limiting combinations include anhydrous MgCl2 and MgCl2-CaCl2 eutectic salt, MgCl2-NaCl eutectic salt and MgCl2-CaCl2 eutectic salt, anhydrous MgCl2 and MgCl2-NaCl eutectic salt, and anhydrous MgCl2 and MgCl2-KCl eutectic salt.

[0060] Preferably, when the deoxidizer in the deoxidation treatment contains magnesium, the weight ratio of the third auxiliary agent to the oxygen-containing Ti6Al4V alloy powder is 0.05 to 3:1, for example, it can be 0.05:1, 0.35:1, 0.75:1, 1.05:1, 1.35:1, 1.65:1, 2.05:1, 2.35:1, 2.65:1 or 3:1, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0061] Preferably, when the deoxidizing agent in the deoxidation treatment contains magnesium, the temperature of the deoxidation treatment is 650-900℃, for example, it can be 650℃, 675℃, 700℃, 735℃, 765℃, 785℃, 815℃, 845℃, 875℃ or 900℃, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0062] Preferably, when the deoxidizing agent in the deoxidation treatment contains magnesium, the deoxidation treatment time is 0.25 to 48 hours, for example, it can be 0.25 hours, 1 hour, 7 hours, 12 hours, 17 hours, 22 hours, 28 hours, 33 hours, 38 hours, 43 hours or 48 hours, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0063] Preferably, when the deoxidizer in the deoxidation treatment contains magnesium, the atmosphere for the deoxidation treatment is a hydrogen-argon mixed atmosphere or a pure hydrogen atmosphere.

[0064] Preferably, the volume fraction of hydrogen in the hydrogen-argon mixed atmosphere is 5% to 100%, for example, it can be 5%, 16%, 27%, 37%, 48%, 58%, 65%, 78%, 90% or 100%, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0065] Preferably, when the deoxidizer in step (2) contains calcium, the mass ratio of the oxygen-containing Ti6Al4V alloy powder to the deoxidizer is 1:0.1 to 1, for example, it can be 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9 or 1:1, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0066] Preferably, when the deoxidizing agent in the deoxidation treatment contains calcium, the deoxidizing agent includes any one or a combination of at least two of the following: powder, shavings, or granules. Typical but non-limiting combinations are a combination of powder and shavings, a combination of granules and shavings, and a combination of powder and granules.

[0067] Preferably, when the deoxidizing agent in the deoxidation treatment contains calcium, a third auxiliary agent is added during the deoxidation treatment.

[0068] Preferably, when the deoxidizing agent in the deoxidation treatment contains calcium, the third auxiliary agent includes any one or a combination of at least two of anhydrous CaCl2, CaCl2-MgCl2 eutectic salt, CaCl2-NaCl eutectic salt, CaCl2-KCl eutectic salt, or CaCl2-LiCl eutectic salt. Typical but non-limiting combinations include anhydrous CaCl2 and CaCl2-MgCl2 eutectic salt, CaCl2-NaCl eutectic salt and CaCl2-MgCl2 eutectic salt, anhydrous CaCl2 and CaCl2-NaCl eutectic salt, anhydrous CaCl2 and CaCl2-KCl eutectic salt, and CaCl2-LiCl eutectic salt and CaCl2-KCl eutectic salt.

[0069] Preferably, when the deoxidizer in the deoxidation treatment contains calcium, the weight ratio of the third auxiliary agent to the oxygen-containing Ti6Al4V alloy powder is 0.05 to 3:1, for example, it can be 0.05:1, 0.35:1, 0.75:1, 1.05:1, 1.35:1, 1.65:1, 2.05:1, 2.35:1, 2.65:1 or 3:1, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0070] Preferably, when the deoxidizing agent in the deoxidation treatment contains calcium, the temperature of the deoxidation treatment is 700-1100℃, for example, 700℃, 745℃, 780℃, 830℃, 870℃, 920℃, 960℃, 1010℃, 1050℃ or 1100℃, etc., but not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0071] Preferably, when the deoxidizing agent in the deoxidation treatment contains calcium, the deoxidation treatment time is 0.25 to 48 hours, for example, it can be 0.25 hours, 1 hour, 7 hours, 12 hours, 17 hours, 22 hours, 28 hours, 33 hours, 38 hours, 43 hours or 48 hours, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0072] Preferably, when the deoxidizing agent in the deoxidation treatment contains calcium, the atmosphere in the deoxidation treatment is a vacuum or a protective atmosphere.

[0073] Preferably, the protective atmosphere for the deoxidation treatment includes any one or a combination of at least two of argon, hydrogen, or helium, wherein typical but non-limiting combinations are combinations of argon and hydrogen, helium and hydrogen, and argon and helium.

[0074] Preferably, the first wet process in step (1) includes: the first reduced product is slurried with water and / or acid to obtain a slurry; the slurry is then subjected to pH adjustment and solid-liquid separation, and the resulting solid phase is then washed and dried to obtain the first reduced powder TiO2. x .

[0075] Preferably, the second wet process in step (1) includes: the product of the second reduction is slurried with water and / or acid to obtain a slurry; the slurry is subjected to pH adjustment and solid-liquid separation in sequence, and the obtained solid phase is washed and dried in sequence to obtain 6Al4V alloy powder.

[0076] Preferably, the third wet process in step (2) includes: the deoxidized product is slurried with water and / or acid to obtain a slurry; the slurry is subjected to pH adjustment and solid-liquid separation in sequence, and the obtained solid phase is washed and dried in sequence to obtain Ti6Al4V alloy powder.

[0077] Preferably, the pH of the acid solution in the first wet treatment, the second wet treatment, and the third wet treatment is independently ≥0.5, for example, it can be 0.5, 0.8, 1, 1.2, 1.4, 1.7, 1.9, 2.1, 2.3, or 2.5, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0078] Preferably, the liquid-to-solid ratio of the slurry in the first, second, and third wet processes is independently 1 to 100:1 mL / g, for example, it can be 1:1 mL / g, 15:1 mL / g, 25:1 mL / g, 35:1 mL / g, 45:1 mL / g, 55:1 mL / g, 65:1 mL / g, 75:1 mL / g, 85:1 mL / g, or 100:1 mL / g, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0079] Preferably, the acid used for pH adjustment in the first wet process, the second wet process, and the third wet process is hydrochloric acid, each independently.

[0080] Preferably, in the pH adjustment of the first wet treatment, the second wet treatment and the third wet treatment, the pH of the slurry is independently controlled to be ≥0.8. For example, it can be 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4 or 2.5, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0081] Preferably, the pH of the slurry after pH adjustment in the first wet treatment, the second wet treatment, and the third wet treatment is independently 1.5 to 3.0, for example, it can be 1.5, 1.7, 1.9, 2, 2.2, 2.4, 2.5, 2.7, 2.9, or 3.0, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0082] In this invention, to prevent the first reducing powder TiO x The 6Al4V alloy powder and Ti6Al4V alloy powder undergo a dissolution reaction with acid during the pH adjustment process. The slurry in the pH adjustment process is preferably controlled at a pH value above 0.8. The pH adjustment is considered to be completed when the pH value stabilizes between 1.5 and 3.0 and no longer changes.

[0083] Preferably, the washing temperatures in the first, second, and third wet treatments are each independently between 0 and 60°C, for example, 0°C, 7°C, 14°C, 20°C, 27°C, 34°C, 40°C, 47°C, 54°C, or 60°C, but are not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0084] Preferably, the drying temperatures in the first, second, and third wet treatments are each independently ≤60℃, for example, 40℃, 43℃, 45℃, 47℃, 49℃, 52℃, 54℃, 56℃, 58℃, or 60℃, but are not limited to the listed values; other unlisted values ​​within this range are also applicable. The drying method is one of atmospheric pressure or vacuum drying or freeze drying at a temperature not exceeding 60℃. In this invention, controlling the drying temperature can effectively prevent the first reduced TiO₂ powder from being reduced. x Excessive oxidation on the surface of Ti6Al4V alloy powder and Ti6Al4V alloy powder is more conducive to controlling the oxygen content level of the final alloy powder.

[0085] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0086] (1) Titanium dioxide is first reduced by a first reducing agent, and the resulting first reducing material is slurried with water and / or hydrochloric acid solution with pH ≥ 0.5 to obtain a slurry; the slurry is pH adjusted, and the pH of the slurry is controlled to be ≥ 0.8 during the pH adjustment process. The pH of the slurry after pH adjustment is stable at 1.5 to 3.0, and then subjected to solid-liquid separation. The obtained solid phase is washed at 0 to 60°C and dried at ≤ 60°C to obtain the first reduced powder TiO2. x , where x≤0.5;

[0087] A mixture of vanadium oxide, calcium oxide, aluminum, and a second auxiliary agent is prepared. The molar ratio of aluminum to vanadium oxide is [(2y+2)a+(2y+3.333)b]:(a+b), where a / (a+b) is the molar percentage of vanadium trioxide in the vanadium oxide, b / (a+b) is the molar percentage of vanadium pentoxide in the vanadium oxide, the molar ratio of calcium oxide to aluminum is 0.6-2:1, y is the molar ratio of aluminum to vanadium in the 6Al4V alloy powder, and the weight ratio of the second auxiliary agent to vanadium oxide is 0.05-3:1. The mixture is subjected to a second reduction at 700-1400℃ for 0.25-24h under vacuum or a protective atmosphere to obtain a second reducing material.

[0088] The second raw material is slurried with water and / or hydrochloric acid solution with pH ≥ 0.5 to obtain a slurry; the slurry is pH adjusted, and the pH of the slurry is controlled to be ≥ 0.8 during the pH adjustment process. The pH of the slurry after pH adjustment is stable at 1.5 to 3.0, and then subjected to solid-liquid separation. The obtained solid phase is washed at 0 to 60°C and dried at ≤ 60°C to obtain 6Al4V alloy powder. The mass ratio of vanadium to aluminum in the 6Al4V alloy powder is 3.5 to 4.5: 5.5 to 6.75.

[0089] (2) The first reducing powder TiO xThe oxygen-containing Ti6Al4V alloy powder is mixed with 6V4Al alloy powder, crushed and granulated, and sintered at 900-1400℃ for 0.25-24h under vacuum or protective atmosphere. The resulting oxygen-containing Ti6Al4V alloy powder is then deoxidized to obtain the deoxidized product.

[0090] The deoxygenated product is slurried with water and / or hydrochloric acid solution with pH ≥ 0.5 to obtain a slurry; the slurry is pH adjusted, and the pH of the slurry is controlled to be ≥ 0.8 during the pH adjustment process. The pH of the slurry after pH adjustment is stable at 1.5 to 3.0, and then subjected to solid-liquid separation. The obtained solid phase is washed at 0 to 60°C and dried at ≤ 60°C to obtain Ti6Al4V alloy powder.

[0091] The present invention does not impose any special restrictions on the solid-liquid separation in the above process. Any device and method known to those skilled in the art for solid-liquid separation can be used. It can also be adjusted according to the actual process. For example, it can be filtration, centrifugation or sedimentation separation, or a combination of different methods.

[0092] Compared with the prior art, the present invention has at least the following beneficial effects:

[0093] (1) The method for preparing Ti6Al4V alloy powder provided by the present invention adds calcium oxide to the aluminum reduction of vanadium oxide, which can control the reduction by-product to a phase that can be wet-processed, so that 6Al4V alloy can be obtained through a short one-step reduction and one-step wet processing, avoiding the high-temperature and complex separation process such as slag-gold separation.

[0094] (2) The method for preparing Ti6Al4V alloy powder provided by the present invention can prepare Ti6Al4V alloy powder using titanium dioxide and vanadium oxide as raw materials, avoiding the preparation of sponge titanium and eliminating the need for a smelting process. The overall process is short and the preparation cost is low.

[0095] (3) The Ti6Al4V alloy powder prepared by the method of the present invention has high purity, low oxygen content and excellent performance. Under better conditions, Ti6Al4V alloy powder with a purity of more than 99.8wt% can be prepared, wherein the oxygen content is ≤0.1wt% and the particle size range can be effectively controlled. Attached Figure Description

[0096] Figure 1 This is a schematic flowchart of the preparation method of Ti6Al4V alloy powder provided by the present invention.

[0097] Figure 2 This is a SEM image of the 6Al4V alloy powder obtained by the second reduction in Example 1 of the present invention.

[0098] Figure 3 yes Figure 2 Elemental analysis diagram of mid-surface scan. Detailed Implementation

[0099] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0100] The present invention will now be described in further detail. However, the examples described below are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0101] As a specific embodiment of the present invention, a method for preparing Ti6Al4V alloy powder is provided, such as... Figure 1 As shown, the preparation method includes the following steps:

[0102] (1) Titanium dioxide undergoes a first reduction with a first reducing agent (aluminum or magnesium) and a first auxiliary agent. When the first reducing agent is aluminum, calcium oxide is also added. The resulting first reduced raw material is then subjected to a first wet process, which includes slurrying the first reduced raw material with water and / or acid to obtain a slurry. The slurry is then pH-adjusted and subjected to solid-liquid separation. The resulting solid phase is washed and dried to obtain first reduced powder TiO2. x , where x≤0.5;

[0103] A second reducing agent is obtained by mixing vanadium oxide with calcium oxide, aluminum as a second reducing agent, and a second auxiliary agent, followed by a second reduction.

[0104] The second reducing material is subjected to a second wet process, which includes slurrying the second reducing material with water and / or acid to obtain a slurry; the slurry is pH adjusted and subjected to solid-liquid separation, and the obtained solid phase is washed and dried to obtain 6Al4V alloy powder, wherein the mass ratio of vanadium to aluminum in the 6Al4V alloy powder is in the range of 3.5-4.5:5.5-6.75;

[0105] (2) The first reducing powder TiO x The oxygen-containing Ti6Al4V alloy powder is mixed, crushed, granulated, and sintered. The resulting oxygen-containing Ti6Al4V alloy powder is then deoxidized by a deoxidizing agent (magnesium or calcium) and a third auxiliary agent to obtain the deoxidized product.

[0106] The deoxidized product is subjected to a third wet process, which includes slurrying the deoxidized product with water and / or acid to obtain a slurry; the slurry is pH adjusted and subjected to solid-liquid separation; the obtained solid phase is washed and dried to obtain Ti6Al4V alloy powder.

[0107] Example 1

[0108] This embodiment provides a method for preparing Ti6Al4V alloy powder, the method comprising the following steps:

[0109] (1) Titanium dioxide was subjected to a first reduction at 1200℃ for 10h under the action of the first reducing agent aluminum (shavings), the first auxiliary agent CaCl2-KCl eutectic salt, and calcium oxide. The molar ratio of aluminum to titanium dioxide was 1.02:1, the molar ratio of calcium oxide to aluminum was 0.8:1, and the weight ratio of CaCl2-KCl eutectic salt to titanium dioxide was 2.5:1, thus obtaining the first reducing material;

[0110] The first reducing agent is slurried in hydrochloric acid solution with a pH of 0.5 to obtain a slurry. The slurry is then pH adjusted, with the pH controlled to be ≥0.8 during the pH adjustment process. After pH adjustment, the pH of the slurry is stabilized at 2.2. The slurry is then filtered, and the resulting solid phase is washed at 45°C and vacuum dried at 55°C to obtain the first reducing powder TiO2. x ;

[0111] A mixed vanadium oxide (vanadium trioxide to vanadium pentoxide in a molar ratio of 2:3) was mixed with calcium oxide, aluminum powder, and CaCl2-KCl eutectic salt. The molar ratio of aluminum powder to vanadium oxide was 42.33:5, the molar ratio of calcium oxide to aluminum powder was 1.5:1, and the weight ratio of CaCl2-KCl eutectic salt to vanadium oxide was 2.5:1. The mixture was subjected to a second reduction at 800℃ for 10 hours under a helium atmosphere to obtain a second reducing material.

[0112] The second raw material is slurried with water to obtain a slurry; the slurry is pH adjusted, and the pH of the slurry is controlled to be ≥0.8 during the pH adjustment process. The pH of the slurry after pH adjustment is stable at 2.5. After filtration, the obtained solid phase is washed at 25°C and vacuum dried at 45°C to obtain 6Al4V alloy powder.

[0113] (2) The first reducing powder TiO x After being mixed with 6V4Al alloy powder, the mixture was ball-milled, spray-granulated, and sintered at 1200℃ for 12 hours under vacuum. The resulting oxygen-containing Ti6Al4V alloy powder was deoxidized at 740℃ for 12 hours using magnesium (granular) as a deoxidizer in a hydrogen-argon mixed atmosphere (hydrogen gas fraction 65%). The mass ratio of oxygen-containing Ti6Al4V alloy powder to deoxidizer was 1:0.4. Anhydrous MgCl2 was added during the deoxidation process, and the weight ratio of anhydrous MgCl2 to oxygen-containing Ti6Al4V alloy powder was 2:1, resulting in the deoxidized product.

[0114] The deoxygenated product is slurried with hydrochloric acid solution at pH 0.8 to obtain a slurry; the slurry is then pH adjusted, with the pH controlled to be ≥ 0.8 during the pH adjustment process. After pH adjustment, the pH of the slurry is stabilized at 1.5, and then filtered. The resulting solid phase is washed at 40°C and vacuum dried at 50°C to obtain Ti6Al4V alloy powder.

[0115] The SEM image of the 6Al4V alloy powder obtained by the second reduction in this embodiment is shown below. Figure 2 As shown, from Figure 2 It can be seen that the 6Al4V alloy powder is spherical, and from Figure 3 It can be seen that the mass fraction of Al is 59.48 wt% and the mass fraction of V is 40.52 wt%, which is consistent with the composition of 6Al4V alloy powder.

[0116] Example 2

[0117] This embodiment provides a method for preparing Ti6Al4V alloy powder, the method comprising the following steps:

[0118] (1) Titanium dioxide was subjected to a first reduction at 900°C for 2 hours under the action of the first reducing agent magnesium (granular) and the first auxiliary agent MgCl2-NaCl eutectic salt. The molar ratio of magnesium to titanium dioxide was 4:1, and the weight ratio of MgCl2-NaCl eutectic salt to titanium dioxide was 2.5:1, thus obtaining the first reducing material.

[0119] The first reducing agent is slurried in hydrochloric acid solution with a pH of 1.0 to obtain a slurry. The slurry is then pH adjusted, with the pH controlled to be ≥1.0 during the pH adjustment process. After pH adjustment, the pH of the slurry is stabilized at 1.5. The slurry is then filtered, and the resulting solid phase is washed at 40°C and vacuum dried at 60°C to obtain the first reducing powder TiO2. x ;

[0120] A second reducing agent was obtained by subjecting a mixture of vanadium oxide (vanadium trioxide to vanadium pentoxide in a molar ratio of 1:3), calcium oxide, aluminum powder, and anhydrous CaCl2, wherein the molar ratio of aluminum powder to vanadium oxide was 34.68:4, the molar ratio of calcium oxide to aluminum powder was 2:1, and the weight ratio of anhydrous CaCl2 to vanadium oxide was 0.05:1, and subjected to a second reduction at 1400℃ for 0.25 h under an argon atmosphere.

[0121] The second raw material is slurried with water to obtain a slurry; the slurry is pH adjusted, and the pH of the slurry is controlled to be ≥0.8 during the pH adjustment process. The pH of the slurry after pH adjustment is stable at 1.5. After filtration, the obtained solid phase is washed at 0°C and vacuum dried at 40°C to obtain 6Al4V alloy powder.

[0122] (2) The first reducing powder TiO x After being mixed with 6V4Al alloy powder, the mixture was ball-milled, spray-granulated, and sintered at 900℃ for 20h under a helium atmosphere. The resulting oxygen-containing Ti6Al4V alloy powder was deoxidized at 650℃ for 48h using magnesium (shavings) as a deoxidizer in a pure hydrogen atmosphere. The mass ratio of oxygen-containing Ti6Al4V alloy powder to deoxidizer was 1:0.1. MgCl2-KCl eutectic salt was added during the deoxidation process, and the weight ratio of MgCl2-KCl eutectic salt to oxygen-containing Ti6Al4V alloy powder was 3:1, resulting in the deoxidized product.

[0123] The deoxygenated product is slurried with hydrochloric acid solution at pH 1.8 to obtain a slurry; the slurry is then pH adjusted, with the pH controlled to be ≥ 1.2 during the pH adjustment process. After pH adjustment, the pH of the slurry is stabilized at 3.0, and then filtered. The resulting solid phase is washed at 0°C and vacuum dried at 40°C to obtain Ti6Al4V alloy powder.

[0124] Example 3

[0125] This embodiment provides a method for preparing Ti6Al4V alloy powder, the method comprising the following steps:

[0126] (1) Titanium dioxide was subjected to a first reduction at 700°C for 10 h in a hydrogen atmosphere under the action of the first reducing agent magnesium (granular) and the first auxiliary agent MgCl2-CaCl2 eutectic salt. The molar ratio of magnesium to titanium dioxide was 2.5:1, and the weight ratio of MgCl2-CaCl2 eutectic salt to titanium dioxide was 0.1:1, thus obtaining the first reducing material.

[0127] The first reducing agent is slurried in hydrochloric acid solution with a pH of 2.5 to obtain a slurry. The slurry is then pH adjusted, with the pH controlled to be ≥0.8 during the pH adjustment process. After pH adjustment, the pH of the slurry is stabilized at 1.5. The slurry is then filtered, and the resulting solid phase is washed at 30°C and vacuum dried at 55°C to obtain the first reducing powder TiO2. x ;

[0128] A mixed vanadium oxide (vanadium pentoxide) was fused with calcium oxide, aluminum powder, and CaCl2-NaCl eutectic salt. The molar ratio of aluminum powder to vanadium oxide was 9.0:1, the molar ratio of calcium oxide to aluminum powder was 0.6:1, and the weight ratio of CaCl2-NaCl eutectic salt to vanadium oxide was 3.0:1. The mixture was subjected to a second reduction at 1400℃ for 0.25 h under an argon atmosphere to obtain a second reducing material.

[0129] The second raw material is slurried with water to obtain a slurry; the slurry is pH adjusted, and the pH of the slurry is controlled to be ≥0.8 during the pH adjustment process. The pH of the slurry after pH adjustment is stable at 3.0. After filtration, the obtained solid phase is washed at 15°C and vacuum dried at 40°C to obtain 6Al4V alloy powder.

[0130] (2) The first reducing powder TiO xAfter being mixed with 6V4Al alloy powder, the mixture was crushed by stirring mill and granulated by drum mill. It was then sintered at 900℃ for 24h under argon atmosphere. The resulting oxygen-containing Ti6Al4V alloy powder was deoxidized at 900℃ for 12h under helium atmosphere using calcium (powder) as a deoxidizer. The mass ratio of oxygen-containing Ti6Al4V alloy powder to deoxidizer was 1:0.15. Anhydrous CaCl2 was added during the deoxidation process, and the weight ratio of anhydrous CaCl2 to oxygen-containing Ti6Al4V alloy powder was 3:1, resulting in the deoxidized product.

[0131] The deoxygenated product is slurried with hydrochloric acid solution at pH 0.5 to obtain a slurry; the slurry is then pH adjusted, with the pH controlled to be ≥ 0.8 during the pH adjustment process. After pH adjustment, the pH of the slurry is stabilized at 2.0, and then filtered. The resulting solid phase is washed at 25°C and vacuum dried at 55°C to obtain Ti6Al4V alloy powder.

[0132] Example 4

[0133] This embodiment provides a method for preparing Ti6Al4V alloy powder, the method comprising the following steps:

[0134] (1) Titanium dioxide was subjected to a first reduction at 1400℃ for 0.25h in a helium atmosphere under the action of the first reducing agent aluminum (powder), the first auxiliary agent CaCl2-LiCl eutectic salt, and calcium oxide. The molar ratio of aluminum to titanium dioxide was 1.33:1, the molar ratio of calcium oxide to aluminum was 0.6:1, and the weight ratio of CaCl2-LiCl eutectic salt to titanium dioxide was 3:1, thus obtaining the first reducing material.

[0135] The first reducing agent is slurried in hydrochloric acid solution with a pH of 2.5 to obtain a slurry. The slurry is then pH adjusted, with the pH controlled to be ≥0.8 during the pH adjustment process. After pH adjustment, the pH of the slurry is stabilized at 2.0. The slurry is then filtered, and the resulting solid phase is washed at 25°C and vacuum dried at 55°C to obtain the first reducing powder TiO2. x ;

[0136] A second reducing agent was obtained by reacting mixed vanadium oxide (vanadium trioxide) with calcium oxide, aluminum (granular) and CaCl2-LiCl eutectic salt, wherein the molar ratio of aluminum to vanadium oxide was 7.666:1, the molar ratio of calcium oxide to aluminum was 1.2:1, and the weight ratio of CaCl2-LiCl eutectic salt to vanadium oxide was 2.2:1. The mixture was then subjected to a second reduction at 1000℃ for 15 hours under a helium atmosphere.

[0137] The second raw material is slurried with hydrochloric acid at pH 1.0 to obtain a slurry; the slurry is then pH adjusted, with the pH controlled to be ≥ 0.8 during the pH adjustment process. The pH of the slurry after pH adjustment is stable at 2.3, and after filtration, the obtained solid phase is washed at 10°C and vacuum dried at 45°C to obtain 6Al4V alloy powder.

[0138] (2) The first reducing powder TiO x After being mixed with 6V4Al alloy powder, the mixture was crushed by tumbling and granulated by pressing. It was then sintered at 1000℃ for 20h in a hydrogen atmosphere. The resulting oxygen-containing Ti6Al4V alloy powder was deoxidized at 700℃ for 24h in a hydrogen atmosphere using calcium (granular) as a deoxidizer. The mass ratio of oxygen-containing Ti6Al4V alloy powder to deoxidizer was 1:0.8. CaCl2-KCl eutectic salt was added during the deoxidation process, and the weight ratio of CaCl2-KCl eutectic salt to oxygen-containing Ti6Al4V alloy powder was 1.3:1, resulting in the deoxidized product.

[0139] The deoxygenated product is slurried with hydrochloric acid solution at pH 0.8 to obtain a slurry; the slurry is then pH adjusted, with the pH controlled to be ≥ 0.9 during the pH adjustment process. After pH adjustment, the pH of the slurry is stabilized at 2.2, and then filtered. The resulting solid phase is washed at 20°C and vacuum dried at 50°C to obtain Ti6Al4V alloy powder.

[0140] Example 5

[0141] This embodiment provides a method for preparing Ti6Al4V alloy powder. Except for replacing the CaCl2-KCl eutectic salt with anhydrous CaCl2 salt in the second reduction step (1), the preparation method is the same as in Example 1.

[0142] Example 6

[0143] This embodiment provides a method for preparing Ti6Al4V alloy powder. Except for the molar ratio of aluminum powder to vanadium oxide in the second reduction step (1) being 50:5, the preparation method is the same as in Example 1.

[0144] Example 7

[0145] This embodiment provides a method for preparing Ti6Al4V alloy powder. Except for the molar ratio of aluminum powder to vanadium oxide in the second reduction step (1) being 40:5, the preparation method is the same as in Example 1.

[0146] Example 8

[0147] This embodiment provides a method for preparing Ti6Al4V alloy powder. Except for the sintering temperature of 1600℃ in step (2), the preparation method is the same as that in Example 1.

[0148] Example 9

[0149] This embodiment provides a method for preparing Ti6Al4V alloy powder. Except for the sintering temperature of 700℃ in step (2), the preparation method is the same as that in Example 1.

[0150] Example 10

[0151] This embodiment provides a method for preparing Ti6Al4V alloy powder. Except for the molar ratio of aluminum to titanium dioxide in the first reduction step (1) being 0.5:1, the preparation method is the same as in Example 1.

[0152] Example 11

[0153] This embodiment provides a method for preparing Ti6Al4V alloy powder. Except for the molar ratio of aluminum to titanium dioxide in the first reduction step (1) being 1.5:1, the preparation method is the same as in Example 1.

[0154] Comparative Example 1

[0155] This comparative example provides a method for preparing Ti6Al4V alloy powder. Except for the fact that calcium oxide is not added in the second reduction step (1), the preparation method is the same as that in Example 1.

[0156] Comparative Example 2

[0157] This comparative example provides a method for preparing Ti6Al4V alloy powder. Except for step (2), which does not involve sintering, the preparation method is the same as that in Example 1.

[0158] Comparative Example 3

[0159] This comparative example provides a method for preparing Ti6Al4V alloy powder. Except for step (2), which does not involve deoxidation treatment and the third wet process, the preparation method is the same as in Example 1.

[0160] Test methods: The oxygen content in Ti6Al4V alloy powder was tested using an ONH analyzer, and the purity of Ti6Al4V alloy powder was tested using ICP-OES. The particle size of Ti6Al4V alloy powder was tested using a particle size distribution analyzer. Furthermore, the TiO2 content in the first reduced powder was tested using ICP-OES and EDS methods. x The content of each element in the 6Al4V alloy powder, and the test results of the above examples and comparative examples are shown in Table 1.

[0161] Table 1

[0162]

[0163]

[0164] The following points can be observed from Table 1:

[0165] (1) As can be seen from Examples 1 to 5, the method for preparing Ti6Al4V alloy powder provided by the present invention can produce Ti6Al4V alloy powder with a purity of more than 99.8wt%, wherein the oxygen content is ≤0.1wt%, and the particle size range can be effectively controlled; the Ti:Al:V mass ratio in the final product meets the requirements.

[0166] (2) It can be seen from the combined examples 1 and 6-7 that the molar ratio of aluminum powder to vanadium oxide in example 1 is 42.33:5, while in examples 6-7 it is 50:5 and 40:5 respectively. The Ti:Al:V mass ratio in the final products of examples 6 and 7 deviates from the nominal composition of Ti6Al4V alloy powder. This shows that the present invention can better obtain Ti6Al4V alloy powder by optimizing the molar ratio of aluminum powder to vanadium oxide.

[0167] (3) It can be seen from the combined examples 1 and 8-9 and Comparative Example 2 that the sintering temperature is too high and does not have any benefit in reducing the oxygen content in Ti6Al4V alloy powder. Moreover, the energy consumption is too high and the requirements for equipment are more stringent. In Example 9, the sintering temperature is only 700℃, resulting in a product purity of only 98.00wt% and an oxygen content as high as 1.95wt%. In Comparative Example 2, no sintering is performed, and Ti6Al4V cannot be fully alloyed. This shows that the present invention can fully alloy titanium, aluminum and vanadium through sintering, and the preferred sintering temperature range can better ensure the purity of Ti6Al4V alloy powder.

[0168] (4) As can be seen from Examples 1 and 10-11, the molar ratio of aluminum to titanium dioxide in the first reduction is crucial for the first reduced TiO2 powder. x The formation of TiO₂ is crucial; when the molar ratio of aluminum to titanium dioxide is low, TiO₂... x If the oxygen content is too high, the alloyed oxygen-containing Ti6Al4V cannot be obtained by full sintering. In Example 11, a Ti-Al-O intermediate is formed in the first reduction, which contains the Ti3Al phase, making subsequent deoxidation difficult. The purity of the Ti6Al4V alloy powder product is only 97.6wt% and the oxygen content is as high as 2.33wt%. This shows that it is more beneficial to obtain high-purity Ti6Al4V alloy powder by controlling the molar ratio of aluminum to titanium dioxide in the first reduction.

[0169] (5) As can be seen from the combined examples 1 and 1, the present invention can make the second reduction byproduct dissolve in dilute acid by adding calcium oxide in the second reduction, and finally obtain vanadium-aluminum alloy. However, in 1, calcium oxide was not added, so the product of the second reduction was difficult to dissolve in dilute acid, and vanadium-aluminum alloy could not be obtained after wet treatment.

[0170] The present invention has been illustrated with the above embodiments to illustrate its detailed structural features. However, the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing Ti6Al4V alloy powder, characterized in that, The preparation method includes the following steps: (1) Titanium dioxide is first reduced by a first reducing agent, and the resulting first reduced raw material is then subjected to a first wet process to obtain first reduced powder TiO2. x Where x≤0.5; the mixture of vanadium oxide and calcium oxide undergoes a second reduction with a second reducing agent and a second auxiliary agent, and the resulting second reducing material is subjected to a second wet process to obtain 6Al4V alloy powder, wherein the mass ratio of vanadium to aluminum in the 6Al4V alloy powder is 3.5~4.5:5.5~6.75; the second reducing agent includes aluminum; (2) Mix the 6Al4V alloy powder and the first reducing powder TiO x After sintering, the oxygen-containing Ti6Al4V alloy powder is subjected to deoxidation treatment and a third wet process to obtain Ti6Al4V alloy powder. In step (1), the molar ratio of the second reducing agent to vanadium oxide is [(2y+2)a+(2y+3.333)b]:(a+b), where a / (a+b) is the molar percentage of vanadium trioxide in vanadium oxide, b / (a+b) is the molar percentage of vanadium pentoxide in vanadium oxide, and y is the molar ratio of aluminum to vanadium in 6Al4V alloy powder; The second auxiliary agent includes any one or a combination of at least two of the following: anhydrous CaCl2, CaCl2-KCl eutectic salt, CaCl2-NaCl eutectic salt, or CaCl2-LiCl eutectic salt; The sintering temperature in step (2) is 900~1400℃; the sintering time is 0.25~24h; When the deoxidizing agent in the deoxidation treatment contains magnesium, the temperature of the deoxidation treatment is 650~900℃, and the time of the deoxidation treatment is 0.25~48h. When the deoxidizing agent in the deoxidation treatment contains calcium, the temperature of the deoxidation treatment is 700~1100℃, and the time of the deoxidation treatment is 0.25~48h. The third wet process described in step (2) includes: the deoxidized product is slurried with water and / or acid to obtain a slurry; the slurry is then subjected to pH adjustment and solid-liquid separation in sequence, and the obtained solid phase is then washed and dried in sequence to obtain Ti6Al4V alloy powder.

2. The preparation method according to claim 1, characterized in that, When the first reducing agent in step (1) is aluminum, the molar ratio of the first reducing agent to titanium dioxide is 1~1.33:

1.

3. The preparation method according to claim 1, characterized in that, When the first reducing agent is aluminum, the first reducing agent includes any one or a combination of at least two of the following: powder, shavings, or granules.

4. The preparation method according to claim 1, characterized in that, When the first reducing agent is aluminum, calcium oxide is added to the first reduction process.

5. The preparation method according to claim 4, characterized in that, When the first reducing agent is aluminum, the molar ratio of calcium oxide to the first reducing agent is 0.6~2:

1.

6. The preparation method according to claim 1, characterized in that, When the first reducing agent is aluminum, a first auxiliary agent is added to the first reduction process.

7. The preparation method according to claim 6, characterized in that, When the first reducing agent is aluminum, the first auxiliary agent includes any one or a combination of at least two of the following: anhydrous CaCl2, KCl, NaCl, CaCl2-KCl eutectic salt, CaCl2-NaCl eutectic salt, CaCl2-LiCl eutectic salt, KCl-NaCl eutectic salt, AlCl3-CaCl2 eutectic salt, AlCl3-KCl eutectic salt, or AlCl3-NaCl eutectic salt.

8. The preparation method according to claim 6, characterized in that, When the first reducing agent is aluminum, the weight ratio of the first auxiliary agent to titanium dioxide is 0.05~3:

1.

9. The preparation method according to claim 1, characterized in that, In step (1), when the first reducing agent is aluminum, the temperature of the first reduction is 700~1400℃.

10. The preparation method according to claim 9, characterized in that, When the first reducing agent is aluminum, the first reduction time is 0.25~24h.

11. The preparation method according to claim 1, characterized in that, When the first reducing agent is aluminum, the atmosphere for the first reduction is a vacuum or a protective atmosphere.

12. The preparation method according to claim 11, characterized in that, When the first reducing agent is aluminum, the protective atmosphere for the first reduction includes any one or a combination of at least two of argon, hydrogen, or helium.

13. The preparation method according to claim 1, characterized in that, In step (1), when the first reducing agent is magnesium, the molar ratio of the first reducing agent to titanium dioxide is 2~4:

1.

14. The preparation method according to claim 1, characterized in that, When the first reducing agent is magnesium, the first reducing agent includes any one or a combination of at least two of the following: powder, shavings, or granules.

15. The preparation method according to claim 1, characterized in that, When the first reducing agent in step (1) is magnesium, the temperature of the first reduction is 600~900℃.

16. The preparation method according to claim 15, characterized in that, When the first reducing agent is magnesium, the first reduction time is 0.25~24h.

17. The preparation method according to claim 1, characterized in that, When the first reducing agent is magnesium, the atmosphere for the first reduction includes any one or a combination of at least two of argon, hydrogen, or helium.

18. The preparation method according to claim 1, characterized in that, The molar ratio of aluminum to vanadium in the 6Al4V alloy powder is 2.833:

1.

19. The preparation method according to claim 1, characterized in that, The second reducing agent includes any one or a combination of at least two of the following: powder, shavings, or granules.

20. The preparation method according to claim 1, characterized in that, In the second reduction process, the molar ratio of calcium oxide to the second reducing agent is 0.6 to 2:

1.

21. The preparation method according to claim 1, characterized in that, The weight ratio of the second auxiliary agent to vanadium oxide is 0.05 to 3:

1.

22. The preparation method according to claim 1, characterized in that, The temperature for the second reduction is 700~1400℃.

23. The preparation method according to claim 22, characterized in that, The second reduction time is 0.25~24h.

24. The preparation method according to claim 1, characterized in that, The second reduction atmosphere is a vacuum or a protective atmosphere.

25. The preparation method according to claim 24, characterized in that, The protective atmosphere for the second reduction includes any one or a combination of at least two of argon, hydrogen, or helium.

26. The preparation method according to claim 1, characterized in that, The mixing process described in step (2) includes: mixing the first reducing powder TiO2... x It is mixed with 6V4Al alloy powder, crushed, and granulated.

27. The preparation method according to claim 26, characterized in that, The crushing method includes any one or a combination of at least two of ball milling, rolling milling, stirring milling, or air jet milling.

28. The preparation method according to claim 26, characterized in that, The granulation method includes any one of spray granulation, roller granulation, or compression granulation.

29. The preparation method according to claim 1, characterized in that, The sintering atmosphere is a vacuum or a protective atmosphere.

30. The preparation method according to claim 29, characterized in that, The protective atmosphere for sintering includes any one or a combination of at least two of hydrogen, argon, or helium.

31. The preparation method according to claim 1, characterized in that, When the deoxidizer in step (2) contains magnesium, the mass ratio of the oxygen-containing Ti6Al4V alloy powder to the deoxidizer is 1:0.05~0.

6.

32. The preparation method according to claim 1, characterized in that, When the deoxidizing agent in the deoxidation treatment contains magnesium, the deoxidizing agent includes any one or a combination of at least two of the following: powder, shavings, or granules.

33. The preparation method according to claim 1, characterized in that, When the deoxidizing agent in the deoxidation treatment contains magnesium, a third auxiliary agent is added during the deoxidation treatment.

34. The preparation method according to claim 33, characterized in that, When the deoxidizing agent in the deoxidation treatment contains magnesium, the third auxiliary agent includes any one or a combination of at least two of anhydrous MgCl2, MgCl2-CaCl2 eutectic salt, MgCl2-NaCl eutectic salt, or MgCl2-KCl eutectic salt.

35. The preparation method according to claim 33, characterized in that, When the deoxidizer in the deoxidation treatment contains magnesium, the weight ratio of the third auxiliary agent to the oxygen-containing Ti6Al4V alloy powder is 0.05~3:

1.

36. The preparation method according to claim 1, characterized in that, When the deoxidizer used in the deoxidation treatment contains magnesium, the atmosphere used in the deoxidation treatment is a hydrogen-argon mixed atmosphere or a pure hydrogen atmosphere.

37. The preparation method according to claim 36, characterized in that, The volume fraction of hydrogen in the hydrogen-argon mixed atmosphere is 5-100%.

38. The preparation method according to claim 1, characterized in that, When the deoxidizer used in the deoxidation treatment contains calcium, the mass ratio of the oxygen-containing Ti6Al4V alloy powder to the deoxidizer is 1:0.1~1.

39. The preparation method according to claim 1, characterized in that, When the deoxidizing agent used in the deoxidation treatment contains calcium, the deoxidizing agent includes any one or a combination of at least two of the following: powder, shavings, or granules.

40. The preparation method according to claim 1, characterized in that, When the deoxidizing agent in the deoxidation treatment contains calcium, a third auxiliary agent is added during the deoxidation treatment.

41. The preparation method according to claim 40, characterized in that, When the deoxidizing agent in the deoxidation treatment contains calcium, the third auxiliary agent includes any one or a combination of at least two of the following: anhydrous CaCl2, CaCl2-MgCl2 eutectic salt, CaCl2-NaCl eutectic salt, CaCl2-KCl eutectic salt, or CaCl2-LiCl eutectic salt.

42. The preparation method according to claim 40, characterized in that, When the deoxidizing agent in the deoxidation treatment contains calcium, the weight ratio of the third auxiliary agent to the oxygen-containing Ti6Al4V alloy powder is 0.05~3:

1.

43. The preparation method according to claim 1, characterized in that, When the deoxidizing agent in the deoxidation treatment contains calcium, the atmosphere in the deoxidation treatment is a vacuum or a protective atmosphere.

44. The preparation method according to claim 43, characterized in that, The protective atmosphere for the deoxidation process includes any one or a combination of at least two of argon, hydrogen, or helium.

45. The preparation method according to claim 1, characterized in that, The first wet process in step (1) includes: the first reduced product is slurried with water and / or acid to obtain a slurry; the slurry is then subjected to pH adjustment and solid-liquid separation, and the resulting solid phase is then washed and dried to obtain the first reduced powder TiO2. x .

46. ​​The preparation method according to claim 1, characterized in that, The second wet process in step (1) includes: the product of the second reduction is slurried with water and / or acid to obtain a slurry; the slurry is subjected to pH adjustment and solid-liquid separation in sequence, and the obtained solid phase is washed and dried in sequence to obtain 6Al4V alloy powder.

47. The preparation method according to claim 1, characterized in that, In the first, second, and third wet treatments, the pH of the acid solution is independently ≥0.

5.

48. The preparation method according to claim 1, characterized in that, In the first, second, and third wet processes, the liquid-to-solid ratio of slurry formation is independently 1 to 100:1 mL / g.

49. The preparation method according to claim 1, characterized in that, The acid used for pH adjustment in the first, second, and third wet processes is hydrochloric acid, which is independent in each process.

50. The preparation method according to claim 1, characterized in that, In the first, second, and third wet treatments, the pH of the slurry is independently controlled to be ≥0.

8.

51. The preparation method according to claim 1, characterized in that, The pH of the slurry after pH adjustment in the first, second, and third wet treatments is independently 1.5 to 3.

0.

52. The preparation method according to claim 1, characterized in that, The washing temperatures in the first, second, and third wet treatments are each independently between 0 and 60°C.

53. The preparation method according to claim 1, characterized in that, The drying temperature in the first, second, and third wet processes is independently ≤60℃.

54. The preparation method according to claim 1, characterized in that, The preparation method includes the following steps: (1) Titanium dioxide is first reduced by a first reducing agent, and the resulting first reducing material is slurried with water and / or hydrochloric acid solution with pH ≥ 0.5 to obtain a slurry; the slurry is pH adjusted, and the pH of the slurry is controlled to be ≥ 0.8 during the pH adjustment process. The pH of the slurry after pH adjustment is stable at 1.5~3.0, and then subjected to solid-liquid separation. The obtained solid phase is washed at 0~60℃ and dried at ≤60℃ to obtain the first reduced powder TiO. x , where x≤0.5; A mixture of vanadium oxide, calcium oxide, aluminum, and a second auxiliary agent is prepared. The molar ratio of aluminum to vanadium oxide is [(2y+2)a+(2y+3.333)b]:(a+b), where a / (a+b) is the molar percentage of vanadium trioxide in the vanadium oxide, b / (a+b) is the molar percentage of vanadium pentoxide in the vanadium oxide, the molar ratio of calcium oxide to aluminum is 0.6~2:1, y is the molar ratio of aluminum to vanadium in the 6Al4V alloy powder, and the weight ratio of the second auxiliary agent to vanadium oxide is 0.05~3:

1. The mixture is subjected to a second reduction at 700~1400℃ for 0.25~24h under vacuum or a protective atmosphere to obtain a second reducing material. The second raw material is slurried with water and / or hydrochloric acid solution with pH ≥ 0.5 to obtain a slurry; the slurry is pH adjusted, and the pH of the slurry is controlled to be ≥ 0.8 during the pH adjustment process. The pH of the slurry after pH adjustment is stable at 1.5~3.0, and then subjected to solid-liquid separation. The obtained solid phase is washed at 0~60℃ and dried at ≤60℃ to obtain 6Al4V alloy powder. The mass ratio of vanadium to aluminum in the 6Al4V alloy powder is 3.5~4.5:5.5~6.

75. (2) The first reducing powder TiO x The oxygen-containing Ti6Al4V alloy powder is mixed with 6V4Al alloy powder, crushed and granulated, and sintered at 900~1400℃ for 0.25~24h under vacuum or protective atmosphere. The resulting oxygen-containing Ti6Al4V alloy powder is then deoxidized to obtain the deoxidized product. The deoxygenated product is slurried with water and / or hydrochloric acid solution with pH ≥ 0.5 to obtain a slurry; the slurry is pH adjusted, and the pH of the slurry is controlled to be ≥ 0.8 during the pH adjustment process. The pH of the slurry after pH adjustment is stable at 1.5~3.0, and then subjected to solid-liquid separation. The obtained solid phase is washed at 0~60℃ and dried at ≤60℃ to obtain Ti6Al4V alloy powder.

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